Electrochemical oxygen reduction for H2O2 production: catalysts, pH effects and mechanisms

Electrochemical oxygen reduction offers an efficient and environmental-friendly route for hydrogen peroxide (H2O2) generation. This electrochemical process can produces H2O2 on-site under ambient conditions. High selectivity and activity two-electron oxygen reduction reaction (2e- ORR) catalysts are crucial for efficient electrochemical H2O2 synthesis. Here, metal/metal oxide, carbon material, and single-atom based 2e- ORR catalysts developed for H2O2 produce are reviewed. As performance of the catalysts strongly depends on the pH values of electrolytes, pH effects and reaction mechanisms for the catalysts are further summarized to give a deep insight into this research area. This review would help us better understand the catalysts for electrochemical H2O2 synthesis and their rational design in the future.